Psychographic targeting and the so called "Weaponized AI Propaganda Machine" have been blamed for swaying public opinion in recent political campaigns. But how effective are they? Why are people so divided on certain topics? And what influences their views? This talk presents the results of five studies exploring each of these questions. The studies examined authoritarianism, threat perception, personality-targeted advertising and biases in relation to support for communication surveillance as a counter-terrorism strategy. We found that people with an authoritarian disposition were more likely to be supportive of surveillance, but that those who are less authoritarian became increasingly supportive of such surveillance the greater they perceived the threat of terrorism. Using psychographic targeting we reached Facebook audiences with significantly different views on surveillance and demonstrated how tailoring pro and anti-surveillance ads based on authoritarianism affected return on marketing investment. Finally, we show how debunking propaganda faces big challenges as biases severely limit a person's ability to interpret evidence which runs contrary to their beliefs. The results illustrate the effectiveness of psychographic targeting and the ease with which individuals' inherent differences and biases can be exploited.